<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      box-sizing: border-box;
    }
    body {
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
      overflow: hidden;
      margin: 0;
    }
    .bg {
      position: absolute;
      height: 100vh;
      width: 100vw;
      z-index: -1;
      filter: blur(30px);
      background: url(./images/road.jpg) no-repeat center center/cover;
    }
    .load-text {
      font-size: 50px;
      color: #fff;
    }
  </style>
</head>
<body>
  <div class="bg"></div>
  <div class="load-text">0%</div>

  <script>
    const bg = document.querySelector(".bg");
    const loadText = document.querySelector(".load-text");

    let load = 0;

    let int = setInterval(blurring, 30);

    function blurring() {
      load++
      let opa = 101 - load;
      let fil = 101 - load;
      let filt;

      if(load > 99) {
        clearInterval(int);
      }
      loadText.innerHTML = `${load}%`;
      loadText.style.opacity = `${opa / 100}`;

      if (fil > 30) {
        fil = 30;
      }
      bg.style.filter = `blur(${fil}px)`;
    };
  </script>
</body>
</html>